import math
 
def f(i,j):
    if i==-1:
        return False
    if i==j:
        return True
    ct=0
 
    for k in range(5):
        if r[i][k]<r[j][k]:
            ct+=1
 
    return ct>=3
 
 
T=int(input())
# T=1
for __ in range(T):
    n=int(input())
    r=[]
    for i in range(n):
        tmp=list(map(int,input().split()))
        r.append(tmp)
    # print(r)
    mx=-1
 
    for i in range(n):
        if f(mx,i):
            continue
        else:
            mx=i
 
    fg=True
    for i in range(n):
        if f(mx,i):
            continue
        else:
            fg=False
 
    if fg:
        print(mx+1)
 
        continue
    print(-1)
 

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4
1
50000 1 50000 50000 50000
3
10 10 20 30 30
20 20 30 10 10
30 30 10 20 20
3
1 1 1 1 1
2 2 2 2 2
3 3 3 3 3
6
9 5 3 7 1
7 4 1 6 8
5 6 7 3 2
6 7 8 8 6
4 2 2 4 5
8 3 6 9 4